Process of producing emulsions or dispersions



L. KIRSCHBRAUN ET AL R l 9 9 l 1 7 6 7- Nov. 13, 1928.'

PROCESS OF PRODUCING EMULSIONS OR DISPERSIONS Original Filed Dec. 1'7,1925 gli.

Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

LESTER KIRSCHBRAUN, OF CHICAGO, ILLINOES, AND HAROLD L. LEVIN, OFPASSAIC,

NEW JERSEY, ASSIGNORS TO THE FLINTKOTE COMPANY, OF BOSTON, MASSACHU-SETTS, A CORPORATION OF MASSACHUSETTS.

PROCESS OF PRODUCING EMULSIONS OR DISPERSIONS.

Original application led December 17, 1925, Serial No. 743,012.

Divided and this application led October 12, 1926. Serial No. 141,138.

This application is a division of our application Serial No. 76,012tiled December 17th, 1925.

This invention relates to improvements in process of producing emulsionsor dispersious of pitch and/or oleaginous bodies ith mineral powderswhich are insoluble in ivatcr but suspendable therein to form a paste orslurry. Such powders comprise clays, b@- tonites, argillaceous minerals,finely divided silicates, metallic oxides and hydroxides, pigments andin general, finely divided mineral products having more or lessplasticity and/or viscosity when suspended or mixed With Water to apaste or slurry form. f

The pitch or oleaginous material dealt with in this connection, includesa wide variety of substances, including bitumens, liquid and solidhydrocarbons, natural and artificial resins, ester gums. stearines,waxes, tempered if desired, With iiuxing oils which may be petroleumproducts, drying or nondrying oils or fatty acids. The more solid ofthese may be generally said to partake of a pitchy nature and possess incommon the property of being immiscible with Water and rendered fusibleor more limpid with heat. They will constitute in this process. the ma.-terial undergoing dispersion or the dispersed phase of the product.

Experience in producing emulsions of the kind referred to has developedthe fact that certain types of pitches and oleaginous bodies emulsitymore readily with particular types of mineral substances of the abovecharacter. lVhile usually some quantity ot' most pit-ches can bedispersed with many kinds ol mineral base, yet the amount of pitchdispersed in many instances is so small as to constitute a minor orinsufficient. portion ot' the resulting product. The resultingdispersion in such cases is so highly loaded with mineral matter thatthe pitchy substance is unable to function as a binder and no utility ofcommercial importance resides in ay product ot such character.

In the course of experience in handling and emulsifying pitchysubstances and combinations such as referred to, it has been tound thata given pitch Would emulsify better with. for instance, one type of claythan another: that in certain instances, combinations of clays affordsuperior emulsive properties; that combinations of bentonites with claysor bentonies with other mineral poivders may aiiordlthe optimum emulsiveproperties tor a `'ivcn pitchy base. Or, given a certain colloidalpaste-i'ornnng emulsitying agent, a change in the character of the pitchoften makes it possible to produce rapidly an emulsion or dispersion,whereas the original or unmodified material would disperse withdifficulty in small quantities or coarsely, it at all.

As a. result ot extended study and observations, it has been discoveredthat one of the most important elements in understanding and controllingthe above described behavior, resides in the hydrogen ion concentra.-tion of the aqueous suspension or paste of the emulsifying agent. It hasbeen further discovered, that the hydrogen ion concentrations of suchsuspensions are not only important of themselves. but must be consideredin relation to the acidic or basic character of the pitch which is to beemulsilied, as well as to the other physical properties of thedispersingagent, such as surface tension. plasticity, degree oftineness, and possibly other factors not vet known.

It will be understood from the nature of the substances referred toabove as pitchy, or employed for dispersion. that some of them may bebasic and some oi them may be of an acidic nature. For example, bothrosiu and stearine pitch are naturally acidic. A tluxing oil such asoleic acid is acidic. Certain grades ot para-cumaron are basic.Asphaltic residues vary trom acidic to basic, the lighter or thinnerresidues such as fuel oil orresiduum from Mexican stock being acidic.the acidity diminishing as the material becomes heavier, passing througha neutral range at certain stages and actually becoming basic with theharder varieties of asphalts.

That this latter is true, may be deduced from the tact that using agiven clay of say, pH 6.() as dispersing agent.l and dispel-singtherebyv a certain amount of say, 19.0 F. melting point. steam refinedMexican asphalt, the pH value ot the resultant dispersion progressivelyincreases with increments of asphalt dispersed. until a point is reachedat Which either no further asphalt can be dispersed and the emulsionbreaks, or the addition of acidic bodies in regulated quantities becomesnecessary to enable further dispersion of the asphalt base to takeplace.

These phenomena become understandable and controllable in the light ofthe hydrogen ion concentration or pH value of the dispersing agent, andthe adjustment of same in relation to the type of pitch undergoingemulsi- {ication or dispersion.

It has been found that clays, bentonites and mineral substances of theclass referred to, vary greatly as to their pH value when suspended inwater, from a noticeable high degree of acidity to a substantialalkalinit-y. Further, combinations of clays or mineral substances whenbrought together, result in modified (though not algebraically additive)pH characteristics. Adjustments of pH value for various dispersingmaterials can be made by a study of the pH Value of the individualmineral powders as well as a study of their pH characteristics whenbrought together in varying proportions. In this way it is possible toprepare a combination of emulsifying minerals of a predetermined pHvalue by either combining them, or by treating them either alone or incombination, with suitable amounts of either basic or acidic substances.

It will of course, be apparent, that the type of water used as thesuspending medium will be of great importance, and must be considered inpredetermining the pH value of the final system. Likewise, the characterof pitch undergoing dispersion and its effect in modifying the pHvalueiof the system must be taken into account.

In order that the general principle of operation may be thoroughlyunderstood, there is presented a drawing showing as an eX- ample, agraphical plot of the pH value of a combination of a number ofbentonitcs with a New Jersey ball clay in varying proportions, pH valuebeing plotted as ordinates and the percentage concentration of each ofthe constitutent mineral dispersing agents as abseiss. There is likewiseexhibited a plot showing the pH characteristics of one of the Bentonitesknown as Type B, with modification by aluminum sulphate Al(1,(so,),.isH2o).

` It will be apparent that a wide range of pH CJi asphalt, will emulsifyquite satisfactorily with a mixture of about one-half Type C or D withone-half Type A clay. If Type B is used in place of the Type C, theemulsive properties of the mixture become decidedly diminished so thatrelatively little asphalt may be dispersed. If it be attempted toeinploy the Type B or the Type C alone, the same result follows. Theoptimum pH Value or range for dispersion of this particular kind ot'pitch is apparently around 6.0-6.5, and by modifying the pH of the T ypeB in any suitable way to achieve this pH, satisfactory dispersion willthen result where no substantial dispersion could be obtained. Thus, bysuccessire attempts to emulsify with emulsifying media of widelydivergent pH values, or, if either of these extremeaalues beunsuccessful. further attempts be made to emulsify with materials haringpH Values intermediate these direi-gent ralues, the range is thuscontinuously narrowed until the optimum point of elnulsitication isfound and the pH Value at this point is thereby disclosed. This sameprocedure followed for any other type of material will disclose theoptimum pH value or range at which it will etliciently disperse largequantities of that material.

lVhile dispersion takes place with this particular pitch under thecondition cited, that is, where the aqueous suspension of the dispersionmeans has a pH of 6.5 (with the particular water used) nevertheless, alimit of the amount of asphalt to be dispersed is reached whenapproximately fifteen times as much asphalt has been dispersed inrelation to the clay. If then the pH value of the system be determined,it will be found that the pH value has increased substantially. If thesystem be treated with an acidic salt or with an acid in regulatedquantities so as to reduce the pH of the system, further quantities ofasphalt can then be dispersed.

Under commercial conditions the dispersion is carried out in acontinuous emulsilier, so that the pH of the final system may beanticipated by adjusting the pH of the aqueous suspension of theemulsifying agent in relation to the effect upon the pH of the pitchundergoing dispersion. done by either treating the dispersion means asdescribed, or introducing the desired amount of reagent into theemulsifying mill, or by introducing a buffer salt which will hold the pHralue or hydrogen ion concentration to within substantiallypredetermined constant limits.

In the previous example given, Mexican asphalt of about 120 F. melt-ingpoint dispersed under the conditions referred to satisfactorily at a pHof between 6.0 to 6.5. As a matter of practical experience in operatinga continuous process, even inside this range, a preferable condition isfound at pH 6.3. It a somewhat harder asphalt is used of the This may be1 llO saine general origin, the best pH conditions are -lound at from6.1 to 6.2. On the other hand where a pitch of entirely diiterentcharacter is employed, such for instance, as steal-ine pitch preparedfrom vegetable oils7 an optimum emulsive condition exists at around pH8.0. It is to be understood ot course, that we do notl in any way wishto limit ourselves to these examples or iiguies as they are merelyillustrative of an optimum condition.

It will thus be seen that by adjusting the pH value or range of theaqueous dispersion means or components of the system, the peculiaritiesot behavior of various emulsitying powders and pitches may be controlledso that practically any en'iulsit'ying mineral in iinely divided itoi'nican be treated to cuiulsity practically any pitch.

Having determined for a given pitch, satisfactory cniulsive conditions.thereafter other dispersion means should be adjusted to the saine pHconditions thus determined.

From the foregoing description it is to be understood that the inventioncontemplates the adjustment of the hydrogen ion conceiitration of theaqueous dispersion media to a pre-determincd pH Value; the maintainingof the hydrogen ion concentration of the aqueous dispersion media withinthe pre-determi-ned pI-I Value range which permits the desireddispersion; and the maintaining of the hydrogen ion concentration ofthesystem while undergoing dispersion within the predetermined pI-I valuerange which Will accomplish this purpose.

By the term pitchy as used in the claims, it is understood that weinclude the wide variety oi substances set forth in one of theintroductory paragraphs ot' this speciiication.

It is understood that the term Yalue as used in the claims, is to bedefined in a bi'oad sense and includes a range of values.

The term electrolyte7 as used in the claims, is intended to include anyacid or acidic salt or any base or basic salt employed thereas, or anysimilar substance capable of ionizing in solution to ail'ect the pHvaluethereof, and does not include emulsifying agents or colloids whichfunction as einulsifying agents, and which att'ect hydrogen ionconcentration.

IVe claim as our invention:

l. In the process of producing a dispersion of a pitch-like substance inan aqueous vehi-l cle. the step of maintaining the hydrogen ionconcentration ot' the aqueous dispersion means at a predetermined pHValue.

Q. In the process of producing a dispersion of a pitchy substance in anaqueous vehicle, the step which includes the addition of a butter saltto hold the hydrogen ion concentration ot the system to withinsubstantially pre-determined constant limits.

3. In the process of producing a dispersion is citer-ted.

5. In the process of producing a dispersion of a pitchy substance in anaqueous vehicle containing insoluble dispersive media, the step whichincludes the addition ot' a buii'er salt to hold the hydrogen ionconcentration Stant limits.

(5. In the process ot' producing a dispersion ol' a pitchy substance inan aqueous vehicle containing insoluble mineral powders, the step whichincludes the addition of a buii'er l ot the system to withinpre-deterinined consalt to hold the hydrogen ion concentration ot thesystem to within pre-determined con stunt limits.

7. In the process of producing a dispersion of a pitchy substance in anaqueous vehicle, the step which includes the addition of an agent tocontrol and maintain a predetermined ion concentration on the systemwhile undergoing dispersion.

8. In the process of producing a dispersion ot' a pitchy substance in anaqueous Vehicle containing an insoluble mineral powder, the step whichincludes the addition ot' an agentto cont-rol and maintain apredetermined hydrogen ion concentration on the system while undergoingdispersion.

In a process o't producing a dispersion in an aqueous vehicle ot' awater repellent base normally iiiiinisciblc with water, the step whichcomprises adjusting the hydrogen ion concenration ot the systemundergoing dispersion to a pre-determined pH value. V'

10. In the process oi producing a dispersion ot' a pitchy substance inan aqueous vehicle, the step ot' adjusting the hydrogen ionconcentra-tion of the aqueous dispersion means to a predetermined valueby combining an electrolyte with said dispersion means.

l1. In the process of producing aqueous bitumen-pitch type dispersions,the steps comprising adjusting the hydrogen ion concentration of anaqueous suspension ot' dispersive media, by combining an electrolytewith said suspension, dispersing pitch with said adjusted suspension.and keeping the mass undergoing dispersion within a relatively narrowrange of pI-I value by the addition ot' a but'fer salt thereto.

12. In the production oiaqueous pitchtype dispersions, the steps whichcomprise making an aqueous suspension of a mineral powder dispersingagent. treating the said suspension with an electrolyte to adjust thehydrogen ion concentration of said suspension to a. predetermined pHvalue, and etllect-Y ing dispersion ot pitch with said adjustedsuspenslon.

13. Tn the production of aqueous bitumenpitch type dispersions, thesteps which coniprise making an aqueous suspension of a clayliltedispersing agent7 treating the said suspension with an electrolyte toadjust the hydrogen ion concentration ot said suspension to apredetermined pH value, and effecting dispersion of pit-ch with saidadjusted suspension.

14. In the production of aqueous bitumenpitch type dispersions, thesteps which comprise making an aqueous suspension of a pluralitj oidispersincr agents. treating' the said .suspension with an electrolyteto adjusty the hydrogen ion concentration ot' said suspension to apredetermined pH value` and effect-- ing dispersion ot pitch with saidadjusted suspension.

l5. In the production of aqueous disper- Patent No. l, 691, 767.

sions ot pitches with dispersive media com- .,justing the hydrogen ionconcentration of said paste to a predetermined pH value, dispersingpitch with said adjusted suspension, continuingthe dispel-sing actionuntil no t'urther substantial quantities of pitch can he dispersed,adjusting the hydrogen ion concentration ot the system whereby to causothe same to permit 'further dispersion ot pitch to he effected therein.and dispersing further quantities of pitch therein.

LESTER KIRSCHBRAUN. HAROLD L. LEVIN.

CERTIFICATE OF CORRECTION.

Granted November 13, 1928, to

LESTER KIRSCHBRAUN and HAROLD L. LEVIN.

"It is hereby certified that the above numbered patent was erroneouslyissued to The Fimtkote Company", as assignee of the entire interest insaid invention, whereas'said patent should have been issued to theinventorsaid "Kirschbraun and Levln said Levin assigner to The FlintkoteCompany, of Boston, Massachusetts a corporation of Massachusetts", asshown by the records of assignments in this' i office: and that the saidetters Patent should be read with this correction therein that the samemay conform lo tite record of the case in the Patent Office Signed andsealed this 8th day of January, A. D. i929. l

(Seal) M. J. Moore, Acting Commissioner of Patents.

